I dont think you are being unreasonable at all, especially since private education had already been discussed, and you have offered 50% custody, more than most mothers would ever dream of doing.

My ex does not pay 1 cent towards his children. CS says he has to pay $5.70 a week (and that is for 2 children, yes, two children!!!!). He can't even manage to do that!
He has his own business (which he obviously dodgies up the books). It is an extremely successful business, he also has his own HUGE home and a healthy supply of drugs. Oh well, I don't really care, I don't want his money and the girls aren't interested in seeing him anymore anyway, especially since they don't even get birthday or xmas cards. Occasionaly a birthday call to say something is on the way (which never arrives), but even those calls are only every couple of years.
I'm sure he makes sure there is just enough contact so that they can not change their surnames to my DH's name without his written permission. GRRRR.

OOps, sorry, I think I just hijakced your post.